JetBlue Airways said Thursday that two of its crew members fell ill aboard a Wednesday night flight from Boston to Charleston, South Carolina. According to the airline, the cause of the odor was nail polish. A representative for the budget carrier confirmed the incident to International Business Times in a statement.

“The crew on JetBlue flight 1667 reported an odor in the cabin,” the airline told IBT. “The aircraft was inspected and the odor was determined to be nail polish remover.”

Airline spokesperson Doug McGraw told the Associated Press that the employees were told to check-in with medical professionals upon the flight landing in South Carolina. No passengers were affected by the odor during the flight. 

Odors have been a frequent perpetrator named in incidents in which crew or passengers have fallen sick on JetBlue Airways flights. Wednesday’s incident was the third in a string of events involving an odor on its flights in just a week, the AP reported. JetBlue Airways said it installed carbon air filters to reduce odors on its aircraft.

One of the airline’s flights from Boston to San Diego, California, last week was forced to make an emergency landing in Buffalo, New York after crew members fell sick. Two flight attendants and the flight’s pilot were transported to a hospital near the Buffalo-Niagara International Airport, MassLive.com reported at the time.

“They were saying that there was an incident on the plane where somebody was having a medical issue,” passenger Michael Feuerstein told Fox-affiliate WFXT in Boston. “People were having headaches on the plane. There were children. The smell could be smelled from the wings of the plane to the actual back of the plane.”

In a separate interview with the Cheektowaga Chronicle, Feuerstein said upon landing that the firefighters called to the scene “walked on board with a carbon monoxide detector to the very back of the airplane where after that it started beeping, extremely, extremely, rapidly.”

A JetBlue Airways flight from California to Florida earlier this month was diverted to Oklahoma City after a foul odor coming from the cockpit caused five of its 135 passengers to experience trouble breathing, IBT previously reported. Passengers were reportedly treated with oxygen tanks to stabilize their breathing after eight ambulances arrived on the scene at the Will Rogers World Airport.

JetBlue Airways JetBlue Airways said Thursday that two of its crew members aboard a Wednesday night flight from Boston to Charleston, South Carolina fell ill. In this photo, travelers walk past the tails of JetBlue airplanes in the airport terminal at Ronald Reagan Washington National Airport in Arlington, Virginia. Photo: Photo credit should read SAUL LOEB/AFP/Getty Images